Hi Alfameister, there are several Car9 builds in progress including a new one just getting started. Seattle Tom's build is the furthest along and he has done a great job with his build log, it has a lot of information for a Car9 builder. Here's the latest picture from his log and you can see he is working on the sheet metal for the scuttle right now. His log is here:
http://www.locostusa.com/forums/viewtopic.php?f=35&t=14613&start=945The drawings on the web site are reasonably up to date. Since then I have been maintaining individual SketchUp files for some of the builders. Right now that includes SeattleTom, Briggs ( a square tube build ) and myself. We have another square tube build starting now. I will be updating the website probably this week to help my new builders.
You can build the frame but we also have FEA models for both the Car9 and Locost frames on this site. Learning these tools is a decent effort but you can really compare how the frames behave to different forces that way.
There are several reasons the Car9 chassis is so much stiffer than the Locost. It includes the roll cage with it's larger tubing, the frame is taller and it includes more triangulation in a few key areas. The basic chassis is 2-3 times stiffer and it's arranged in a way that a simple radius rod can be added from the middle of the dash across the passenger seat to the outside rail. This little tube weighs 2-3 pounds but adds perhaps %50 to the cars stiffness because it creates a well triangulated cockpit. I thought it was a neat little trick, it only works if the places the tube connects are well triangulated thru the rest of the frame. For track use I think it's a reasonable compromise.
A couple other sensible features are that the roll bar is well braced to strong frame areas that are triangulated to take large forces and the rear is protected by a pair of rear facing hoops made of roll cage material.
Car9 also manages this stiffness without a tube frame around the driveshaft, so you gain a couple of inches of cockpit space there. It uses a couple of solid bar hoops around the driveshaft for safety.
Wessonality, I am sorry I missed your post. I try to check this site a couple of times a day, but things get by me sometimes.. I'll try to email you or PM.